Fluid collection canister with integrated moisture trap

ABSTRACT

A moisture trap for removing liquid from fluid from a tissue site treated with reduced pressure are described. The moisture trap may include a barrier adapted to be fluidly coupled to and define an indirect fluid path between a fluid reservoir and a reduced-pressure source. The barrier may have a hydrophilic surface. The moisture trap also may include a sump adapted to receive condensation from the barrier.

Under 35 U.S.C. §119(e), this application claims priority to and thebenefit of U.S. Provisional Patent Application No. 61/784,734 filed Mar.14, 2013, entitled “Wound Fluid Collection Canister with IntegratedCondensation Inhibitor,” the disclosure of which is hereby incorporatedby reference in its entirety.

TECHNICAL FIELD

The present disclosure relates generally to medical treatment systemsfor treating tissue sites and processing fluids. More particularly, butnot by way of limitation, the present disclosure relates to a canisterhaving a device for the removal of liquid from a fluid.

BACKGROUND

Clinical studies and practice have shown that reducing pressure inproximity to a tissue site can augment and accelerate growth of newtissue at the tissue site. The applications of this phenomenon arenumerous, but is has proven particularly advantageous for treatingwounds. Regardless of the etiology of a wound, whether trauma, surgery,or another cause, proper care of the wound is important to the outcome.Treatment of wounds with reduced pressure may be commonly referred to as“reduced-pressure wound therapy,” but is also known by other names,including “negative-pressure therapy,” “negative pressure woundtherapy,” and “vacuum therapy,” for example. Reduced-pressure therapymay provide a number of benefits, including migration of epithelial andsubcutaneous tissues, improved blood flow, and micro-deformation oftissue at a wound site. Together, these benefits can increasedevelopment of granulation tissue and reduce healing times.

While the clinical benefits of reduced-pressure therapy are widelyknown, the cost and complexity of reduced-pressure therapy can be alimiting factor in its application, and the development and operation ofreduced-pressure systems, components, and processes continues to presentsignificant challenges to manufacturers, healthcare providers, andpatients.

SUMMARY

According to an illustrative embodiment, a system for treating a tissuesite with reduced pressure is described. The system may include adressing adapted to be placed adjacent to the tissue site and a canisterhaving a fluid reservoir adapted to be fluidly coupled to the dressing.A moisture trap may be fluidly coupled to the fluid reservoir. Themoisture trap may include a barrier and a sump adapted to receivecondensation from the barrier. A reduced-pressure source may be adaptedto be fluidly coupled to the moisture trap. The barrier may include ahydrophilic surface and define an indirect fluid path between the fluidreservoir and the reduced-pressure source.

According to another illustrative embodiment, a moisture trap forremoving liquid from fluids from a tissue site treated with reducedpressure is described. The moisture trap may include a barrier adaptedto be fluidly coupled to and define an indirect fluid path between afluid reservoir and a reduced-pressure source. The barrier may have ahydrophilic surface. The moisture trap also may include a sump adaptedto receive condensation from the barrier.

According to yet another illustrative embodiment, a method for treatinga tissue site with reduced pressure is described. A reduced-pressuredressing may be disposed adjacent to the tissue site and fluidly couplea reduced-pressure source to the reduced-pressure dressing. Reducedpressure can be supplied to the reduced-pressure dressing with thereduced-pressure source, and fluid may be drawn from the tissue sitewith the reduced-pressure dressing and the reduced-pressure source. Thefluid may be collected in a fluid reservoir in a canister fluidlycoupled between the reduced-pressure dressing and the reduced-pressuresource. The fluid may be moved through an indirect fluid path that maybe fluidly coupled between the canister and the reduced-pressure source.The indirect fluid path may be formed by a barrier having a hydrophilicsurface to condense liquids from the fluids. The condensed liquid may bechanneled from the hydrophilic surface to a sump to store the condensedliquids.

According to still another illustrative embodiment, a method ofmanufacturing a moisture trap for removing liquid from fluids from atissue site treated with reduced pressure is described. A barrier may beadapted to be fluidly coupled between a fluid reservoir and areduced-pressure source, the barrier having a hydrophilic surface. Thebarrier may be positioned between the fluid reservoir and thereduced-pressure source to define an indirect fluid path. A sump may beprovided and adapted to receive condensation from the barrier.

Other aspects, features, and advantages of the illustrative embodimentswill become apparent with reference to the drawings and detaileddescription that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is sectional view illustrating an exemplary embodiment of areduced-pressure therapy system in accordance with this specification;

FIG. 2 is a perspective view of an illustrative canister of thereduced-pressure therapy system of FIG. 1;

FIG. 3 is a sectional view of the canister of FIG. 2 having a moisturetrap;

FIG. 4A is a perspective view of an illustrative plate of the moisturetrap of FIG. 2;

FIG. 4B is a detailed perspective view of a portion of the plate of FIG.4A;

FIG. 5 is an elevation view of another embodiment of a plate of themoisture trap of FIG. 2;

FIG. 6 is a perspective view of another illustrative embodiment of amoisture trap that may be used with the reduced-pressure therapy systemof FIG. 1;

FIG. 7 is a partial sectional perspective view of the moisture trap ofFIG. 6;

FIG. 8 is a detail sectional view of a portion of an illustrativecanister having another embodiment of a moisture trap that may be usedwith the reduced-pressure therapy system of FIG. 1;

FIG. 9 is a top view of an example of cellular material that can be usedwith the moisture trap of FIG. 8;

FIG. 10 is an elevation view of the cellular material of FIG. 9;

FIG. 11 is a detail sectional view of a portion of another illustrativecanister having another example embodiment of a moisture trap that maybe used with the reduced-pressure therapy system of FIG. 1; and

FIG. 12 is a perspective view of an example mesh material that can beused with the moisture trap of FIG. 11.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

New and useful systems, methods, and apparatuses for removing liquidfrom fluid drawn from a tissue site in a reduced-pressure therapyenvironment are set forth in the appended claims. Objectives,advantages, and a preferred mode of making and using the systems,methods, and apparatuses may be understood best by reference to thefollowing detailed description in conjunction with the accompanyingdrawings. The description provides information that enables a personskilled in the art to make and use the claimed subject matter, but mayomit certain details already well-known in the art. Moreover,descriptions of various alternatives using terms such as “or” do notnecessarily require mutual exclusivity unless clearly required by thecontext, and reference to “an” item generally refers to one or more ofthose items. The claimed subject matter may also encompass alternativeembodiments, variations, and equivalents not specifically described indetail. The following detailed description should therefore be taken asillustrative and not limiting.

The example embodiments may also be described herein in the context ofreduced-pressure therapy applications, but many of the features andadvantages are readily applicable to other environments and industries.Spatial relationships between various elements or to the spatialorientation of various elements may be described as depicted in theattached drawings. In general, such relationships or orientations assumea frame of reference consistent with or relative to a patient in aposition to receive reduced-pressure therapy. However, as should berecognized by those skilled in the art, this frame of reference ismerely a descriptive expedient rather than a strict prescription.

FIG. 1 is a sectional view of one embodiment of a therapy system 100 forsupplying reduced pressure to a tissue site 102 that can remove liquidfrom fluid drawn from the tissue site 102. As illustrated, the therapysystem 100 may include a dressing 104, a canister 106, and areduced-pressure source 108. The dressing 104, the canister 106, and thereduced-pressure source 108 may be fluidly coupled by one or moreconduits, such as a tube 110 fluidly coupling the dressing 104 to thecanister 106, and a tube 112 fluidly coupling the canister 106 to thereduced-pressure source 108.

The term “tissue site” in this context broadly refers to a wound ordefect located on or within tissue, including but not limited to, bonetissue, adipose tissue, muscle tissue, neural tissue, dermal tissue,vascular tissue, connective tissue, cartilage, tendons, or ligaments. Awound may include chronic, acute, traumatic, subacute, and dehiscedwounds, partial-thickness burns, ulcers (such as diabetic, pressure, orvenous insufficiency ulcers), flaps, and grafts, for example. The term“tissue site” may also refer to areas of any tissue that are notnecessarily wounded or defective, but are instead areas in which it maybe desirable to add or promote the growth of additional tissue. Forexample, reduced pressure may be used in certain tissue areas to growadditional tissue that may be harvested and transplanted to anothertissue location.

In general, components of the therapy system 100 may be coupled directlyor indirectly. For example, reduced-pressure source 108 may be directlycoupled to the canister 106 and indirectly coupled to the dressing 104through the canister 106. Components may be fluidly coupled to eachother to provide a path for transferring fluids (i.e., liquid and/orgas) between the components. In some embodiments, components may befluidly coupled with the tube 110 and the tube 112, for example. A“tube,” as used herein, broadly refers to a tube, pipe, hose, conduit,or other structure with one or more lumina adapted to convey fluidsbetween two ends. Typically, a tube may be an elongated, cylindricalstructure with some flexibility, but the geometry and rigidity may vary.In some embodiments, components may additionally or alternatively becoupled by virtue of physical proximity, being integral to a singlestructure, or being formed from the same piece of material. Coupling mayalso include mechanical, thermal, electrical, or chemical coupling (suchas a chemical bond) in some contexts.

The fluid mechanics of using a reduced-pressure source to reducepressure in another component or location, such as within a sealedtherapeutic environment, can be mathematically complex. However, thebasic principles of fluid mechanics applicable to reduced-pressuretherapy are generally well-known to those skilled in the art, and theprocess of reducing pressure may be described illustratively herein as“delivering,” “distributing,” or “generating” reduced pressure, forexample.

In general, exudates and other fluids flow toward lower pressure along afluid path. This orientation may generally be presumed for purposes ofdescribing various features and components of reduced-pressure therapysystems herein. Thus, the term “downstream” typically implies somethingin a fluid path relatively closer to a reduced-pressure source, andconversely, the term “upstream” implies something relatively furtheraway from a reduced-pressure source. Similarly, it may be convenient todescribe certain features in terms of fluid “inlet” or “outlet” in sucha frame of reference. However, the fluid path may also be reversed insome applications (such as by substituting a positive-pressure sourcefor a reduced-pressure source) and this descriptive convention shouldnot be construed as a limiting convention.

“Reduced pressure” generally refers to a pressure less than a localambient pressure, such as the ambient pressure in a local environmentexternal to a sealed therapeutic environment provided by the dressing104. In many cases, the local ambient pressure may also be theatmospheric pressure at which a tissue site is located. Alternatively,the pressure may be less than a hydrostatic pressure associated withtissue at the tissue site. Unless otherwise indicated, values ofpressure stated herein are gauge pressures. Similarly, references toincreases in reduced pressure typically refer to a decrease in absolutepressure, while decreases in reduced pressure typically refer to anincrease in absolute pressure.

The dressing 104 generally may include a cover, such as a drape 114, atissue interface, such as a manifold 116, and a connector, such as anadapter 118. In operation, the manifold 116 may be placed within, over,on, or otherwise proximate to a tissue site, such as the tissue site102. The drape 114 may be placed over the manifold 116 and sealed totissue proximate to the tissue site 102. The tissue proximate to thetissue site 102 is often undamaged epidermis peripheral to the tissuesite 102. Thus, the dressing 104 can provide a sealed therapeuticenvironment proximate to the tissue site 102 that may be substantiallyisolated from the external environment, and the reduced-pressure source108 can reduce the pressure in the sealed therapeutic environment.Reduced pressure applied across the tissue site 102 through the manifold116 in the sealed therapeutic environment can induce macrostrain andmicrostrain in the tissue site 102, as well as remove exudates and otherfluids from the tissue site 102. Exudate and other fluid from the tissuesite 102 can be collected in the canister 106 and disposed of properly.

The drape 114 may be an example of a sealing member. A sealing membermay be constructed from a material that can provide a fluid seal betweentwo components or two environments, such as between a therapeuticenvironment and a local external environment. The sealing member may be,for example, an impermeable or semi-permeable elastomeric material thatcan provide a seal adequate to maintain a reduced pressure at a tissuesite for a given reduced-pressure source. For semi-permeable materials,the permeability generally should be low enough that a desired reducedpressure may be maintained. An attachment device may be used to attach asealing member to an attachment surface, such as undamaged epidermis, agasket, or another sealing member. The attachment device may take manyforms. For example, an attachment device may be a medically acceptable,pressure-sensitive adhesive that may extend about a periphery, a portionof, or an entirety of the sealing member. Other example embodiments ofan attachment device may include a double-sided tape, paste,hydrocolloid, hydrogel, silicone gel, organogel, or an acrylic adhesive.

The manifold 116 can be generally adapted to contact the tissue site102. The manifold may be partially or fully in contact with the tissuesite 102. If the tissue site 102 is a wound, for example, the manifold116 may partially or completely fill the wound, or may be placed overthe wound. The manifold 116 may take many forms, and may have manysizes, shapes, or thicknesses depending on a variety of factors, such asthe type of treatment being implemented or the nature and size of thetissue site 102. For example, the size and shape of the manifold 116 maybe adapted to the contours of deep and irregular shaped tissue sites.

More generally, a manifold may be a substance or structure adapted todistribute reduced pressure across a tissue site, remove fluids fromacross a tissue site, or distribute reduced pressure and remove fluidsacross a tissue site. In some embodiments, a manifold may alsofacilitate delivering fluids to a tissue site, if the fluid path isreversed or a secondary fluid path is provided, for example. A manifoldmay include liquid channels or pathways that distribute fluids providedto and removed from a tissue site around the manifold. In someillustrative embodiments, the liquid channels or pathways may beinterconnected to improve distribution or removal of fluids across atissue site. For example, cellular foam, open-cell foam, porous tissuecollections, and other porous material, such as gauze or felted mat,generally include structural elements arranged to form liquid channels.Liquids, gels, and other foams may also include or be cured to includeliquid channels.

In one illustrative embodiment, the manifold 116 may be a porous foammaterial having interconnected cells or pores adapted to distributereduced pressure across the tissue site 102. The foam material may beeither hydrophobic or hydrophilic. In one non-limiting example, themanifold 116 can be an open-cell, reticulated polyurethane foam such asGranuFoam® dressing available from Kinetic Concepts, Inc. of SanAntonio, Tex.

In an example in which the manifold 116 may be made from a hydrophilicmaterial, the manifold 116 may also wick fluid away from the tissue site102, while continuing to distribute reduced pressure to the tissue site102. The wicking properties of the manifold 116 may draw fluid away fromthe tissue site 102 by capillary flow or other wicking mechanisms. Anexample of a hydrophilic foam may be a polyvinyl alcohol, open-cell foamsuch as V.A.C. WhiteFoam® dressing available from Kinetic Concepts, Inc.of San Antonio, Tex. Other hydrophilic foams may include those made frompolyether. Other foams that may exhibit hydrophilic characteristicsinclude hydrophobic foams that have been treated or coated to providehydrophilicity.

The manifold 116 may further promote granulation at the tissue site 102if pressure within the sealed therapeutic environment is reduced. Forexample, any or all of the surfaces of the manifold 116 may have anuneven, coarse, or jagged profile that can induce microstrains andstresses at the tissue site 102 if reduced pressure is applied throughthe manifold 116.

In one embodiment, the manifold may be constructed from bioresorablematerials. Suitable bioresorbable materials may include, withoutlimitation, a polymeric blend of polylactic acid (PLA) and polyglycolicacid (PGA). The polymeric blend may also include without limitationpolycarbonates, polyfumarates, and capralactones. The manifold 116 mayfurther serve as a scaffold for new cell-growth, or a scaffold materialmay be used in conjunction with the manifold 116 to promote cell-growth.A scaffold is generally a substance or structure used to enhance orpromote the growth of cells or formation of tissue; such as athree-dimensional porous structure that provides a template for cellgrowth. Illustrative examples of scaffold materials include calciumphosphate, collagen, PLA/PGA, coral hydroxy apatites, carbonates, orprocessed allograft materials.

A reduced-pressure source, such as the reduced-pressure source 108, maybe a reservoir of air at a reduced pressure, or may be a manually orelectrically-powered device that can reduce the pressure in a sealedvolume, such as a vacuum pump, a suction pump, a wall suction portavailable at many healthcare facilities, or a micro-pump, for example.The reduced-pressure source may be housed within or used in conjunctionwith other components, such as sensors, processing units, alarmindicators, memory, databases, software, display devices, or userinterfaces that further facilitate reduced-pressure therapy. While theamount and nature of reduced pressure applied to a tissue site may varyaccording to therapeutic requirements, the pressure typically rangesbetween −5 mm Hg (−667 Pa) and −500 mm Hg (−66.7 kPa). Commontherapeutic ranges are between −75 mm Hg (−9.9 kPa) and −300 mm Hg(−39.9 kPa).

The canister 106 may be representative of a container, canister, pouch,or other storage component that can be used to manage exudate and otherfluid withdrawn from a tissue site. In many environments, a rigidcontainer may be preferred or required for collecting, storing, anddisposing of fluid. In other environments, fluid may be properlydisposed of without rigid container storage, and a re-usable containercould reduce waste and costs associated with reduced-pressure therapy.The canister 106 may be fluidly coupled to the dressing 104 with thetube 110 and fluidly coupled to the reduced-pressure source 108 with thetube 112. The reduced-pressure source 108 supplies reduced pressure tothe canister 106 through the tube 112 and to the dressing 104 throughthe canister 106 and the tube 110. In this manner, the reduced-pressuresource 108 may draw fluid, including exudate from the tissue site 102into the canister 106.

During operation of a reduced-pressure therapy system, areduced-pressure source may draw fluid from a tissue site into acanister, such as the canister 106. The fluid drawn from a tissue sitemay have a high content of evaporated liquid, giving the fluid a highrelative humidity. If a canister is coupled to a tissue site through atube, as in therapy system 100, a portion of the evaporated liquid maycondense in the tube. This may occur due to the cooler ambientenvironment surrounding the tube, for example. The fluid, including thecondensed liquid in the tube, may be drawn into the canister by thereduced-pressure source.

Once the fluid reaches a canister, additional liquid may condense fromthe fluid in the canister. Despite the condensation, the fluids in acanister may have a relative humidity as high as about 70%, for example.This relative humidity depends, in part, on the ambient temperaturearound a canister, the location of the canister, the orientation of thecanister, how much liquid may be in the canister, and the type ofliquid, including exudate, in the canister.

If a canister is coupled to a reduced-pressure source through anothertube, as in therapy system 100, humid fluid may also be drawn from acanister into the tube coupled to the reduced-pressure source. There,further liquid may condense from the fluid in the tube. The condensedliquid in the tube may be drawn into the reduced-pressure source, whichmay cause the reduced-pressure source to operate improperly or stopfunctioning altogether.

In other embodiments, a canister and reduced-pressure source may bejointly housed within an integral therapy unit. These units may faceproblems similar to those described above, as highly humid fluid may bedrawn from the canister into the reduced-pressure source.

To address this problem, some canisters may expel the highly humid fluidonto an inside face of the canister before drawing the fluid into areduced-pressure source. There, the fluid can cool and liquid maycondense out of the fluid. The condensation on the inside face of thecanister may cause the canister to appear to be leaking. Other canistersexpel fluid from the canister into an internal location of a combinedcanister and reduced-pressure source unit. In these canisters, liquidcan condense from the fluids within this structure and can cause thecanister to appear to be contaminated. Condensed liquid within thestructure may also lead to the growth of flora. Growth of flora withinthe structure may lead to growth of flora elsewhere in a therapy systemthat may be detrimental to the health of the person receivingreduced-pressure therapy. Still other canisters may expel the fluiddirectly into a pump chamber of a reduced-pressure source. Condensedliquid in a pump chamber can cause failure of pump seals, failure ofelectrical connections within the pump, and a reduced ability to providereduced-pressure therapy. Systems having a higher fluid flow tolerancemay experience a magnification of the problems described above.

As disclosed herein, the therapy system 100 can overcome theseshortcomings and others by providing a moisture trap associated with thecanister that can reduce the liquid content of fluid leaving thecanister 106. For example, in some embodiments of the therapy system100, a moisture trap may be fluidly coupled between a fluid reservoir ofthe canister 106 and a reduced-pressure source 108. At least one barriermay be disposed within some embodiments of the moisture trap, providingan indirect fluid path between the fluid reservoir and thereduced-pressure source 108. The barrier preferably comprises ahydrophilic material or a hydrophilic surface. A sump may also bedisposed within the moisture trap in fluid communication with thebarrier to receive liquid condensed thereon.

FIG. 2 is a perspective view illustrating additional details that may beassociated with an example embodiment of the canister 106. As shown, thecanister 106 may include a fluid outlet, such as an opening 124, and afilter 126 disposed within the opening 124. The filter 126 may be ahydrophobic filter, for example, configured to limit or reduce thenumber of particulates, including liquids, passing through the opening124. In some embodiments, an adapter or connector (not shown) may bedisposed over the opening 124 to facilitate coupling between the opening124 and a tube, such as the tube 112. The canister 106 may also includethree pairs of opposing walls, such as, end walls 128, side walls 129,and top and bottom walls 131.

FIG. 3 is a sectional view illustrating additional details that may beassociated with example embodiments of the canister 106. As shown inFIG. 3, the canister 106 may also include a fluid inlet, such as port122. The port 122 may facilitate coupling the canister 106 to a tube,such as the tube 110. In other embodiments, the opening 124 and the port122 may be located on other portions of the canister 106.

As illustrated in the example embodiment of FIG. 2, the end walls 128,the side walls 129, and the top and bottom walls 131 form a six-sidedbody. The end walls 128, the side walls 129, and the top and bottomwalls 131 each join adjacent walls at an approximately ninety degreeangle. In other exemplary embodiments, the canister 106 may haveflexible walls or other shapes, for example, spherical or pyramidal.

As shown, the end walls 128 couple to the top and bottom walls 131 andthe side walls 129 to form a fluid reservoir 120. The illustrativecanister 106 also may include a moisture trap 130. The moisture trap 130in this example embodiment may be fluidly coupled between the fluidreservoir 120 and the reduced-pressure source 108. As illustrated, forexample, the moisture trap 130 can be disposed within the canister 106proximate to the opening 124 so that fluid flowing from the fluidreservoir 120 passes through the moisture trap 130 before passingthrough the opening 124.

The moisture trap 130 generally may include a first wall 132, a secondwall 134, and at least one fluid barrier, such as a plate 138. Asillustrated in FIG. 3, the first wall 132 and the second wall 134 canjoin at ends of each wall at an angle of approximately 90 degrees. Thefirst wall 132 and the second wall 134 may be joined at opposite ends tothe walls of the canister 106 that form the fluid reservoir 120. In someembodiments, the moisture trap 130 may be secured to or otherwisedisposed adjacent to the opening 124 without joining the first wall 132or the second wall 134 to the walls of the canister 106. The first wall132 may generally be parallel to the opening 124 and separated from theopening 124 by a distance 136. The distance 136 may be a portion of atotal length of the canister 106. In some embodiments, the distance 136may extend a majority of the length of the canister 106. In otherembodiments, the distance 136 may extend less than about one-half of thelength of the canister 106. As illustrated, in some embodiments thesecond wall 134 may generally be perpendicular to the first wall 132. Inthe illustrated embodiment, the first wall 132 and the second wall 134fluidly isolate a portion of the fluid reservoir 120 proximate to theopening 124 from the remaining portions of the fluid reservoir 120.

The first wall 132 may have an opening 133 similar to the opening 124,as illustrated in FIG. 3. The opening 133 can permit fluid communicationbetween the fluid reservoir 120 and the moisture trap 130. A filter 135may be disposed within the opening 133. The filter 135 may be similar tothe filter 126 and may be a hydrophobic filter configured to limit orreduce the number of particulates, including liquids, passing throughthe opening 133.

As illustrated in FIG. 3, the moisture trap 130 may also include a sump,such as the sump 140. In some embodiments, the sump 140 may be disposedadjacent to the second wall 134 and perpendicular to the first wall 132,as illustrated. The sump 140 may consist of or include a layer ofmaterial having a thickness less than a height of the first wall 132 andmay extend the width of the moisture trap 130 between the side walls 129of the canister 106. For example, the sump 140 may include an absorbentmaterial disposed within the moisture trap 130 to collect liquidcondensed from fluid flowing through the moisture trap 130. In someembodiments, the thickness of the absorbent material may vary as neededfor the particular application of the moisture trap 130. In someembodiments, the sump 140 may extend only a portion of the width of themoisture trap 130 to allow the sump 140 to expand as the sump 140receives liquid, for example. In the illustrative embodiment of FIG. 3,the sump 140 may be fluidly isolated from the fluid reservoir 120 sothat liquid in the fluid reservoir 120 may not interact with the sump140.

The liquid condensed from the fluid flowing through the moisture trap130 may primarily be water, making materials formed of super absorbentpolymers suitable for efficient use as the sump 140. In some embodimentsthe sump 140 may be sodium polyacrylate. In other embodiments, the sump140 may be BASF Luquasorb® or Luquafleece® 402C; Technical AbsorbentsLimited superabsorbent fibers, such as TAL 2327; Texsus spa FP2325; oran isolyser. In still other embodiments, the sump 140 may be anabsorbent having carboxymethyl cellulose or alginates.

As illustrated in FIG. 3, a fluid barrier can be disposed between thefirst wall 132 and the opening 124. A fluid barrier may be a deviceconfigured to impede, restrict, or otherwise direct fluid flow. Forexample, the fluid barrier of FIG. 3 may include three plates 138disposed in the fluid path between the opening 124 and the opening 133.A plate, such as the plate 138, may be a generally rectangular piece ofmaterial. In some embodiments, a plate may be a solid piece ofrectangular material. Each plate 138 may have a first end that can bejoined to a wall. As shown in FIG. 3, for example, a first plate 138 mayhave a first end that joins to the second wall 134; a second plate 138may have a first end that joins to a wall forming a portion of thecanister 106; and a third plate 138 may have a first end that joins tothe second wall 134. Each plate 138 in this example embodiment may havea second end separated from the wall proximate to the second end. Theseparation may form a gap between the wall proximate to the second endand the second end of each plate 138. Sides of each plate 138 that areperpendicular to the first end and the second end may be joined to theside walls 129 forming the canister 106 and the fluid reservoir 120 sothat fluid communication around each plate 138 may only occur across thesecond end of each plate 138.

Each plate 138 may be in a parallel juxtaposition, for example, eachplate 138 may be positioned so that the plate 138 may be parallel to thefirst wall 132 and to adjacent plates 138. Each plate 138 may also bedisposed within the moisture trap 130 and oriented so that a plane inwhich the plate 138 is disposed may intersect a plane in which the sump140 is disposed. For example, the plates 138 may all be perpendicular tothe sump 140 in some embodiments. In other embodiments, the plates 138may not be perpendicular to the sump 140, but may also not be parallelto the sump 140. In the illustrated embodiment, the first end of a plate138 proximate to the first wall 132 may be joined to the second wall 134so that fluid passes between the second end of the plate 138 and the topwall of the top and bottom walls 131 forming an exterior of the canister106.

The plate 138 proximate to the opening 124 may also be joined to thesecond wall 134 so that there may be a gap between the second end of theplate 138 and the top wall 131 forming the exterior of the canister 106.The plate 138 disposed near a center portion of the second wall 134 maybe joined to the top wall 131 forming an exterior of the canister 106 sothat there may be a gap between the second end of the plate 138 and thesecond wall 134. In this manner, the plates 138 form an indirect fluidpath between the opening 133 and the opening 124. In this context, an“indirect” fluid path may be a fluid path between two locations havingat least one change of direction between the two locations. An indirectfluid path may also be referred to as a “tortuous” fluid path, a“labyrinthine” fluid path, or a “convoluted” fluid path.

FIG. 4A is a perspective view illustrating additional details that maybe associated with some embodiments of the plates 138 of FIG. 3. Asillustrated, the plate 138 may include one or more liquid channels 144disposed on a surface of the plate 138, such as a condensation surface142. A channel, such as the channel 144, may be a portion of the plate138 configured to direct liquid by providing a preferential path forliquid flow. In some embodiments, the plate 138 may include the liquidchannels 144 on both sides of the plate 138. The condensation surface142 may be preferably a hydrophilic surface, either wholly or in part. Asurface that is hydrophilic may be a surface treated with a material orformed from a material that is molecularly attractive to water. In theillustrated embodiments, the condensation surface 142 may be a portionof the plate 138 formed of a hydrophilic material or having ahydrophilic material disposed thereon.

Additionally or alternatively, the liquid channels 144 may behydrophobic in some embodiments. Hydrophobic materials may be materialsthat are treated with or formed from a material that is molecularlyrepulsive to water. For example, the liquid channels 144 may be formedof a hydrophobic material or have a hydrophobic material disposedthereon, which may facilitate movement of liquid through the liquidchannels 144. In the illustrated embodiment, the plate 138 may have acollection end 148 and a drainage end 150. The plate 138 may be orientedwithin the moisture trap 130 so that the drainage end 150 may beproximate to or adjacent to the sump 140. The liquid channels 144 mayform pathways configured to direct condensed liquid toward the drainageend 150 and the sump 140. In the embodiment of FIG. 4A, for example, theliquid channels 144 include a central channel 145 proximate to a centerportion of the plate 138, and the central channel 145 may have aterminus 147 proximate to the drainage end 150. Tributary channels 149may extend from the edges of the plate 138 toward the central channel145 and generally toward the drainage end 150 so that the liquidchannels 144 form a fletching pattern. As illustrated, the tributarychannels 149 in the example embodiment of FIG. 4A are generallyconfigured to direct liquid from outer portions of the plate 138 towardthe central channel 145. Preferably, the plate 138 may be orientedwithin the moisture trap 130 so that the liquid channels 144 may beaided by gravity.

FIG. 4B is a detail perspective view illustrating additional detailsthat may be associated with the example embodiment of the plate 138illustrated in FIG. 4A. In some embodiments, the condensation surface142 may have a rough finish. For example, the condensation surface 142may have bumps, nodules, protuberances or other forms of protrusions,illustrated in FIG. 4B as protrusions 146. In some embodiments, theprotrusions 146 may protrude between about 15 microns and about 20microns from the surrounding condensation surface 142, and are alsopreferably hydrophilic. The protrusions 146 may be spherical, conical,pyramidal, grooves, other polygons, or may have an amorphous orirregular shape, for example. In some embodiments, the protrusions 146may be formed by injection molding, stamping, hot or cold rolling,chemical and photo lithographic etching, micro machining, or bead, sand,or vapor blasting of the plate 138.

In some embodiments, the barrier in the moisture trap 130 may be aporous plate, mesh, net, or fabric that permits fluid to flow throughit. The porous plate, mesh, net, or fabric forms an indirect fluid flowpath as the porous plate, mesh, net, or fabric may impede the flow offluid from the opening 133 to the opening 124. In addition, the porousplate, mesh, net, or fabric may be formed of a plurality ofobstructions, such as the fibers of a woven fabric that may cause thefluid to change directions in response to interaction with theobstruction; thus, such obstructions form an indirect fluid path betweenthe opening 133 and the opening 124. For example, if each plate 138 is aporous plate and extends from the top wall 131 to the second wall 134,then fluid can flow through the plate 138 rather than around the plate138.

The porous plate, mesh, net, or fabric may be formed of a hydrophilicmaterial, or be treated to impart hydrophilic properties to thematerial. In addition, the liquid channels 144 may be formed on theporous plate, mesh, net, or fabric. In some embodiments, the porousplate, mesh, net, or fabric may have a wax coating to form the liquidchannels 144. In other embodiments, the liquid channels 144 may beformed on the porous plate, mesh, net, or fabric versions of the plate138, for example, the area of the material where the liquid channels 144are desired could be fused together and treated to impart hydrophobicproperties. The porous plate, mesh, net, or fabric versions of the plate138 may be formed from a woven or non-woven material, a foam, a sinteredpolymer or formed from a solid piece of material formed to have pores.Nets or meshes may be extruded or expanded to increase the flow area;however, the surface area available for condensation should bemaximized. In addition, the porous plate, mesh, net, or fabric versionsof the plate 138 may be stacked or layered with additional plates 138.

The plate 138 may be manufactured from a hydrophilic material, forexample, and then treated to form the liquid channels 144. Formation ofthe liquid channels 144 may be accomplished by plasma coating, forexample. In plasma coating, plasma may be used to deposit a thin coatingof a compound designed to alter the level of hydrophilicity. Forexample, the plasma coating processes developed by P2i Limited may beused to form the liquid channels 144. In other embodiments, the plate138 may be formed of a hydrophobic material. The plate 138 may then betreated to form the condensation surface 142. Formation of thecondensation surface 142 may be done with a plasma coating process or awet coating process, for example. In some embodiments, a wet coatingprocess or a chemical vapor deposition process may be used to depositParylene to form the condensation surface 142. In other embodiments, acorona or plasma coating process may oxidize the surface of the plate138 to form the condensation surface 142. Hydak® manufactured byBiocoat, Inc. may also be used to treat the plate 138 to form thecondensation surface 142. In some embodiments, the plate 138 may notinclude the liquid channels 144. In these embodiments, the condensationsurface 142 may encompass the entirety of the plate 138. Generally, inembodiments having both the condensation surface 142 and the liquidchannels 144, the condensation surface 142 may be greater than or equalto about 80% of the plate 138.

FIG. 5 is a front view of another embodiment of a plate that may be usedas a fluid barrier in some embodiments of the moisture trap 130. Asshown in FIG. 5, a plate 238 may include a collection end 248, adrainage end 250, a condensation surface 242, and one or more liquidchannels 244. The plate 238 may be of a similar size, have similarproperties, and operate in a manner similar to the plate 138 of FIG. 4A.As shown in FIG. 5, the liquid channels 244 may have additional shapesas desired to direct liquid as needed in the particular embodiment ofthe moisture trap 130.

In operation, the reduced-pressure source 108 can supply reducedpressure to the dressing 104 through the canister 106, drawing fluidfrom the tissue site 102 into the fluid reservoir 120 through the port122. Fluid may be stored in the fluid reservoir 120 and fluid havingevaporated liquid therein may be drawn into the moisture trap 130through the opening 133. The filter 135 may prevent condensed liquidfrom passing from the fluid reservoir 120 into the moisture trap 130 sothat fluid entering the moisture trap 130 may be composed primarily ofgas and evaporated liquid.

The reduced-pressure source 108 can also draw the gas and evaporatedliquid through the indirect fluid path provided by the moisture trap130. Fluid having gas and evaporated liquid may be exposed to a surfaceof each plate 138 as it moves through the indirect fluid path of themoisture trap 130. For example, as fluid passes through the opening 133,the indirect fluid path formed by the plates 138 can direct fluid towardthe top wall 131 forming the exterior of the canister 106 around thesecond end of the plate 138 and toward the second wall 134 so that thefluid on a first side of the plate 138 flows in an opposite directionfrom fluid flowing on a second side of the plate 138. In someembodiments, the indirect fluid path can move fluid in opposingdirections on opposite sides of each plate 138.

The condensation surface 142 may be a portion of the plate 138 that isattractive to liquid so that liquid evaporated in fluid flowing adjacentto the condensation surface 142 of the plate 138 may be urged tocondense from the fluid onto the condensation surface 142. As the gasand evaporated liquid flow across the condensation surfaces 142, theprotrusions 146 and the hydrophilic properties of the condensationsurfaces 142 can cause the evaporated liquid to condense onto thecondensation surfaces 142. The protrusions 146 may aid in condensationby acting as preferential sites for nucleation that condenses liquidfrom the fluid passing by the condensation surface 142. The protrusions146 may also aid in moving liquid condensed onto the condensationsurface 142 toward the liquid channels 144. As liquid is condensed, theliquid may be urged toward the sump 140 by the liquid channels 144. Ifthe liquid reaches the sump 140, the liquid may be trapped by the sump140. In this manner, the liquid content of fluid leaving the canister106 may be reduced.

FIG. 6 is a perspective view illustrating another example embodiment ofa moisture trap 330, and FIG. 7 is a cut-away view illustratingadditional details of the moisture trap 330. The moisture trap 330 mayoperate in a manner similar to the moisture trap 130, modified asdescribed in more detail below. In the illustrated embodiment, themoisture trap 330 may be a cylindrical body having a top wall 302, abottom wall 304, and a cylindrical side wall 306. The cylindrical sidewall 306 may be coupled to a peripheral portion of the bottom wall 304and to a peripheral portion of the top wall 302. The top wall 302, thebottom wall 304, and the cylindrical side wall 306 form an interior 308,which can be fluidly isolated from an ambient environment.

The illustrative embodiment of the moisture trap 330 also may include afluid inlet 333 and a fluid outlet 324. The fluid inlet 333 may bedisposed proximate to the cylindrical side wall 306 and a peripheralportion of the bottom wall 304. The fluid outlet 324 may be disposedproximate to a center portion of the top wall 302 and be may generallybe aligned with an axis of the moisture trap 330. Both the fluid inlet333 and the fluid outlet 324 may be cylindrical bodies configured to befluidly coupled to a conduit so that the moisture trap 330 may bedisposed in a fluid path between a fluid reservoir and areduced-pressure source. For example, the moisture trap 330 may befluidly coupled between the fluid reservoir 120 of the canister 106 andthe reduced-pressure source 108 of FIG. 1. Filters 335 and 326 may alsobe disposed within the fluid inlet 333 and the fluid outlet 324,respectively. The filters 335 and 326 may be similar to the filters 135and 126 of FIG. 1, and may also be formed of a hydrophobic material. Thefluid inlet 333 may have a cylindrical wall extending into the interior308 from the bottom wall 304 so that a terminus of the fluid inlet 333may be separated from an interior surface of the bottom wall 304.

The moisture trap 330 also may include a sump 340, which may be similarin many respects to the sump 140. In the illustrative embodiment of FIG.7, for example, the sump 340 may be disposed adjacent to the bottom wall304. The sump 340 may include a layer of absorbent material having athickness less than the height of the cylindrical side wall 306 and maybe coextensive with the bottom wall 304. In some embodiments, thethickness of the absorbent material may vary as needed for theparticular application of the moisture trap 330. In some embodiments,the sump 340 may not be coextensive with the bottom wall 304 of themoisture trap 330 to allow the sump 340 to expand as the sump 340receives liquid, for example. The sump 340 can be fluidly isolated froma fluid reservoir so that liquid in the fluid reservoir may not interactwith the sump 340.

Liquid condensed from fluid flowing through the moisture trap 330 mayprimarily be water, making materials formed of super-absorbent polymerssuitable for efficient use as the sump 340. In some embodiments the sump340 may be sodium polyacrylate. In other embodiments, the sump 340 maybe BASF Luquasorb® or Luquafleece® 402C; Technical Absorbents Limitedsuperabsorbent fibers, such as TAL 2327; Texsus spa FP2325; or anisolyser. In still other embodiments, the sump 340 may be an absorbenthaving carboxymethyl cellulose or alginates.

The moisture trap 330 also may include a fluid barrier, such as a spiralbarrier 338. The spiral barrier 338 may be similar to the plate 138 insome respects. The spiral barrier 338 may be an Archimedean spiralhaving a first end 310, a second end 312, and opposing lateral edges314, 316. The spiral barrier 338 may have other spiral shapes such asCornu, Fermat, hyperbolic, lituus, or logarithmic spirals, for example.The spiral barrier 338 may be disposed within the interior 308 so thatthe first end 310 may be proximate to the fluid inlet 333 and the secondend 312 may be proximate to the fluid outlet 324. In the illustratedembodiment, the first end 310 may be adjacent to the cylindrical sidewall 306 so that fluid may not flow between the first end 310 and thecylindrical side wall 306. In other embodiments, the first end 310 maybe proximate to the cylindrical side wall 306 and allows fluid flowbetween the first end 310 and the cylindrical side wall 306. Theopposing lateral edges 314, 316 may be coupled to the top wall 302 andthe bottom wall 304, respectively, to prevent fluid communicationbetween the opposing lateral edges 314, 316 and the top wall 302 and thebottom wall 304.

The spiral barrier 338 may also include condensation surfaces and liquidchannels similar to the condensation surfaces 142 and the liquidchannels 144 of the plate 138. The condensation surfaces may operatesimilar to the condensation surface 142 and the liquid channels maydirect fluid to the sump 340 similar to the liquid channels 144. Thecondensation surfaces and the liquid channels may also be formed in amanner similar to the condensation surface 142 and the liquid channels144.

The spiral barrier 338 may be a single member formed to have the spiralshape. The spiral barrier 338 may be manufactured by rolling a strip ofa plate-like material to form the desired shape, for example. In someembodiments, a strip of material may be bent to form the desired shape.In still other embodiments, the spiral barrier 338 may be formed ofmultiple members joined to form the spiral shape.

In operation, fluid may enter the moisture trap 330 through the fluidinlet 333 proximate to the first end 310 of the spiral barrier 338, andmay flow adjacent to the surface of the spiral barrier 338. The curve ofthe spiral barrier 338 may be adapted to direct fluid along a spiralpath toward the second end 312 of the spiral barrier 338 proximate tothe fluid outlet 324. In this manner, the spiral barrier 338 forms anindirect fluid path between the fluid inlet 333 and the fluid outlet 324by changing the direction of the fluid as the fluid flows between thefluid inlet 333 and the fluid outlet 324. In some embodiments, as fluidflows adjacent to the spiral barrier 338, hydrophilic condensationsurfaces may cause liquid to condense from the fluid onto the surface ofthe spiral barrier 338.

FIG. 8 is a partial sectional view illustrating details of anotherillustrative embodiment of a moisture trap 430 that may be associatedwith the therapy system 100. A portion of a canister 406 is alsoillustrated in FIG. 8, having the illustrative moisture trap 430disposed therein. The canister 406 may be similar to the canister 106 inmany respects, and generally may include a fluid outlet 424 having afilter 426 disposed therein. The fluid outlet 424 may be similar to andoperate like the opening 124 and the fluid outlet 324, and the filter426 may be similar to and operate like the filter 126 and the filter 326described above. The canister 406 may include an end wall 428 and a topwall 431. The end wall 428 and the top wall 431 may be similar to andoperate in a manner similar to the end walls 128 and the top and bottomwalls 131 of FIG. 2. The example embodiment of the moisture trap 430illustrated in FIG. 8 generally may include a first wall 432 and asecond wall 434, which may be joined orthogonally. The second wall 434may be joined at an opposite end to the end wall 428 of the canister406. The first wall 432 may generally be parallel to the fluid outlet424 and separated from the fluid outlet 424 by a distance 436. Thedistance 436 may be a portion of a total length of the canister 406. Insome embodiments, the distance 436 may extend a majority of the lengthof the canister 406. In other embodiments, the distance 436 may extendless than about one-half of the length of the canister 406. The secondwall 434 may generally be perpendicular to the first wall 432. Both thefirst wall 432 and the second wall 434 may have side ends perpendicularto the first end and the second end that join to the side walls formingthe canister 406.

The first wall 432 may extend from the second wall 434 toward the topwall 431 of the canister 406 a portion of the distance between thesecond wall 434 and the top wall 431 of the canister 406. This may forman opening 433 that permits fluid communication between the moisturetrap 430 and a fluid reservoir of the canister 406. In some embodiments,the first wall 432 may join the top wall 431 of the canister 406 and theopening 433 may be formed in the first wall 432 similar to the firstwall 132 and the opening 133. A filter may be disposed within theopening 433. In the example embodiment of FIG. 8, the opening 433 doesnot have a filter.

The moisture trap 430 may also include a sump 440. In the illustratedembodiment, the sump 440 may be disposed adjacent to the second wall 434and perpendicular to the first wall 432. The sump 440 may include anabsorbent layer having a thickness less than the height of the firstwall 432, and may be coextensive with the second wall 434 in someembodiments. In some embodiments, the thickness of the absorbent layermay vary as needed for the particular application of the moisture trap430. In some embodiments, the sump 440 may extend only a portion of thesecond wall 434 of the moisture trap 430 to allow the sump 440 to expandas the sump 440 receives fluid, for example. The sump 440 can be fluidlyisolated from the fluid reservoir in some embodiments so that liquid inthe fluid reservoir may not interact with the sump 440.

Liquid condensed from the fluid flowing through the moisture trap 430may primarily be water, making materials formed of super absorbentpolymers suitable for efficient use as the sump 440. In some embodimentsthe sump 440 may be sodium polyacrylate. In other embodiments, the sump440 may be BASF Luquasorb® or Luquafleece® 402C; Technical AbsorbentsLimited superabsorbent fibers, such as TAL 2327; Texsus spa FP2325; oran isolyser. In still other embodiments, the sump 440 may be anabsorbent having carboxymethyl cellulose or alginates.

As illustrated in FIG. 8, the moisture trap 430 may also include abarrier, such as an array 438 of cells 450. FIG. 9 is a top view of thearray 438, and FIG. 10 is side elevation view of the array 438,illustrating additional details that may be associated with someembodiments. The array 438 may include a cluster of individual cells 450having cell walls 452. Generally, a cell, such as each cell 450, may bea component that may be combined with other substantially identicalcomponents to form a whole. The cell walls 452 of each cell 450 may beinterconnected or shared with the cell walls 452 of adjacent cells 450so that the plurality of cells 450 form the interconnected structure ofthe array 438. In the illustrated embodiment, each cell 450 may have ahexagonal shape with six cell walls 452. In other embodiments, each cell450 may have a circular, square, triangular, rhomboidal, or amorphousshape. The cell walls 452 in the illustrative embodiment may each form achannel 460 extending through each cell 450 from a first end 456 to asecond end 458. The cell walls 452 may have a length 454 so that eachcell 450 may extend from the top wall of the top and bottom walls 431 ofthe canister 406 to the sump 440. Each channel 460 may be open at thesecond end 458 of the cell 450 so that the channel 460 may be in fluidcommunication with the sump 440. In some embodiments, the channel 460may be open at the first end 456.

Each cell wall 452 may include a plurality of perforations 462. Theperforations 462 may extend through the cell wall 452 so that fluid maycommunicate through the cell wall 452. In some embodiments, theperforations 462 may permit fluid communication between the channel 460and an ambient environment, for example a fluid reservoir of thecanister 406. The perforations 462 may also permit fluid communicationbetween the channels 460 of adjacent cells 450 having an interconnectedcell wall 452. In the illustrated embodiment, each cell 450 may have adistance between parallel sides, that is, across the flats, of about 6mm. The size of the cells 450 may be reduced to increase the availablesurface area provided the by cell walls 452, thus increasing the abilityof the cells 450 to cause condensation. In addition, the size of thecells 450 may be increased to reduce the flow restriction through themoisture trap 430, if desired. The cells 450 may be formed of athermoplastic and may have hydrophilic properties. In some embodiments,the cells 450 may be formed of a material such as those manufactured byBaltex, Plascore, Inc., or Hexacor Limited. In some embodiments, thesematerials may be referred to as a 3-D fabric. 3-D fabrics may bematerials having the flexibility associated with fabric while havinglength, width, and depth. Some 3-D fabrics may be formed similar to thearray 438 described above. Other 3-D fabrics may be formed having twolayers of woven material joined by a plurality of fibers. The materialmay also be treated similar to the plate 138 to vary the hydrophilictyof the material as desired for the particular application of the array438.

As shown in FIG. 8, the array 438 can be disposed between the sump 440and the top wall 431 of the canister 406 so that the array 438 canprovide a barrier to fluid flow between a fluid reservoir of thecanister 406 and the fluid outlet 424. The array 438 may be coupled tothe top wall 431 and side walls of the canister 406 so that the fluidpath flows through the array 438. The fluid may flow through the array438 by passing through the perforations 462 in each cell wall 452. Inthe illustrated embodiment, each cell 450 may be hexagonal and joined toat least two adjacent cells 450 so that the perforations 462 may notform a straight flow path from the opening 433 to the fluid outlet 424.

In operation, the reduced-pressure source 108 can supply reducedpressure to the dressing 104 through the canister 406, drawing fluidfrom the tissue site 102 into the canister 106. Fluid may be stored in afluid reservoir of the canister 106 and fluid having evaporated liquidtherein may be drawn into the moisture trap 430 through the opening 433.The reduced-pressure source 108 can also draw the gas and evaporatedliquid through an indirect fluid path formed by the array 438. As fluidpasses through a perforation 462 in a first cell wall 452 of a cell 450the fluid may change direction to reach the fluid outlet 424. If fluidto passes through a perforation 462 in a first cell wall 452 and notchange direction, the fluid flow should eventually abut the top wall431, the side walls of the canister 406, or the second wall 434 beforereaching the fluid outlet 424. The top wall 431 and the side walls ofthe canister 406 or the second wall 434 can cause a change in thedirection of the fluid flow. In this manner, the plurality of cells 450can form an indirect fluid path. The array 438 can provide a largecondensation area by increasing the surface area that the fluid maycontact as it passes through the moisture trap 430. As gas andevaporated liquid flow across the surfaces of the cells 450, evaporatedliquid can condense onto the cell walls 452. As liquid is condensed, theliquid may be urged toward the sump 440 by the channels 460. If liquidreaches the sump 440, the liquid may be trapped by the sump 440. In thismanner, the moisture content of fluid leaving the canister 406 may bereduced. In some embodiments, the sump 440 and the array 438 may bejoined to form a multi-function fluid management laminate.

FIG. 11 is a side sectional view illustrating another example embodimentof a moisture trap 530 disposed in a canister 506. The canister 506 maybe similar to the canister 106 in many respects, modified as describedbelow. The canister 506 in this example embodiment generally may includea fluid outlet 524 having a filter 526 disposed therein. The fluidoutlet 524 may be similar to and operate like the opening 124, the fluidoutlet 324, and the fluid outlet 424, and the filter 526 may be similarto and operate like the filter 126, the filter 326, and the filter 426described above. The canister 506 may have an end wall 528 and a topwall 531. The end wall 528 and the top wall 531 may be similar to andoperate in a manner similar to the end walls 128 and the top wall 131 ofthe canister 106 described above with respect to FIG. 2. Theillustrative embodiment of the moisture trap 530 generally may include afirst wall 532, a second wall 534, and a mesh barrier 538 having anupper layer 550, a lower layer 552, and a mesh layer 554. The first wall532 and the second wall 534 may join at ends of each wall at an angle ofapproximately 90 degrees. The second wall 534 may be joined at anopposite end to the wall 528 of the canister 506. The first wall 532 maygenerally be parallel to the fluid outlet 524 and separated from thefluid outlet 524 by a distance 536. The distance 536 may be a portion ofa total length of the canister 506. In some embodiments, the distance536 may extend a majority of the length of the canister 506. In otherembodiments, the distance 536 may extend less than about one-half of thelength of the canister 506. The second wall 534 may generally beperpendicular to the first wall 532 and join the walls forming thecanister 506 proximate to the fluid outlet 524. Both the first wall 532and the second wall 534 have side ends perpendicular to the first endand the second end that may join to the side walls forming the canister506. The first wall 532 may extend a portion of the perpendiculardistance between the second wall 534 and the top wall 531 of thecanister 506, forming an opening 533 that can permit fluid communicationbetween the moisture trap 530 and a fluid reservoir of the canister 506.In some embodiments, the first wall 532 may join the top wall 531 of thecanister 506 and the opening 533 can be formed in the first wall 532,similar to the first wall 432 and the opening 433. A filter may bedisposed within the opening 533. In the illustrated embodiment, theopening 533 does not have a filter.

As illustrated, the example embodiment of the moisture trap 530 also mayinclude a sump 540. The sump 540 may be disposed adjacent to the secondwall 534 perpendicular to the first wall 532. The sump 540 may include alayer of absorbent material having a thickness less than the height ofthe first wall 532, and may be coextensive with the second wall 534. Insome embodiments, the thickness of the absorbent material may vary asneeded for the particular application of the moisture trap 530. In someembodiments, the sump 540 may not be coextensive with the second wall534 of the moisture trap 530 to allow the sump 540 to expand as the sump540 receives liquid, for example. In the illustrated embodiment, thesump 540 may be fluidly isolated from a fluid reservoir so that liquidsin the fluid reservoir may not interact with the sump 540. The sump 540may be an absorbent material disposed within the moisture trap 530 tocollect liquid condensed from fluid flowing through the moisture trap530.

Liquid condensed from fluid flowing through the moisture trap 530 mayprimarily be water, making materials formed of super-absorbent polymerssuitable for efficient use as the sump 540. In some embodiments the sump540 may be sodium polyacrylate. In other embodiments, the sump 540 maybe BASF Luquasorb® or Luquafleece® 402C; Technical Absorbents Limitedsuperabsorbent fibers, such as TAL 2327; Texsus spa FP2325; or anisolyser. In still other embodiments, the sump 540 may be an absorbenthaving carboxymethyl cellulose or alginates.

FIG. 12 is a perspective view illustrating additional details of themesh barrier 538. The illustrative mesh barrier 538 of FIG. 12 generallymay include the upper layer 550, the lower layer 552, and the mesh layer554. The mesh barrier 538 may be oriented within the moisture trap 530so that the upper layer 550 may be adjacent to the top wall 531 of thecanister 506, and the lower layer 552 may be adjacent the sump 540. Themesh layer 554 can be disposed between and fluidly coupled to the upperlayer 550 and the lower layer 552. The mesh barrier 538 may extend theentirety of the distance between the sump 540 and top wall 531. In someembodiments, the top wall 531 may be parallel to the sump 540 so thatfluid flowing in the moisture trap 530 may flow through the mesh barrier538. The upper layer 550 and the lower layer 552 may be wicking layersin some embodiments, configured to draw liquid into the mesh layer 554or into the sump 540. The mesh layer 554 may be formed of a yarn, forexample, which may be treated or coated to have hydrophilic properties.The yarn may be manufactured from different materials with differenthydrophilic, hydrophobic, or absorbent properties. In addition, the typeof yarn can also be varied to vary the width of the mesh layer 554 andthe mesh barrier 538. In other embodiments, the mesh barrier 538 may bea spacer fabric produced by a knitting process, similar to thosemanufactured by Heathcoat Fabrics and Muler Textil. In one embodiment,the mesh barrier 538 may be a material formed of hydrophilic fibersformed of Nylon 6/6, such as polyester.

In operation, fluid can flow through the opening 533, encountering themesh layer 554. The mesh layer 554 may be disposed in the fluid pathbetween the opening 533 and the fluid outlet 524, causing fluid to flowin an indirect fluid path. Fibers forming the mesh layer 554 may causefluid to make numerous changes of direction as fluid flows through themesh layer 554. As fluid interacts with the mesh layer 554, hydrophilicproperties of the mesh layer 554 may cause liquid to condense from thefluid. The mesh layer 554 may direct liquid along fibers of the meshlayer 554 into the lower layer 552. The lower layer 552 may wick liquidinto the sump 540, where liquid can be stored. Fluid that may flowthrough the upper layer 550 may be directed into the mesh layer 554,where the mesh layer 554 may then cause liquid to condense from thefluid as described above.

The systems and methods described herein may provide significantadvantages, some of which have already been mentioned. For example, theillustrative moisture traps can significantly reduce liquid content offluid that exits a canister. The moisture traps may also preventcondensate from appearing in places where liquid should not be andprevent condensed liquid from providing a false perception that thedevice or canister may have been damaged or may be leaking. The moisturetraps may also reduce the maintenance and service costs of a device. Inmany applications, the moisture traps can also make efficient use of asump having a super-absorbent, as a super-absorbent sump can absorb morepure water condensed from fluid. In some embodiments, the moisture trapsmay also trap volatile organic compounds and other airborne particulatesas liquid condenses. Some embodiments of the moisture traps may alsohelp to dispose of fluidly contaminated components. Some embodiments ofthe moisture traps can be incorporated into a canister with minimal costand may be retrofitted to other standard (Bemis type) canisters. Stillfurther, some embodiments of the moisture traps may be replaceable witheach canister.

It should be apparent from the foregoing that an invention havingsignificant advantages has been described. While shown in only a fewforms, the systems and methods illustrated are susceptible to variouschanges and modifications without departing from the spirit thereof.

Although certain illustrative, non-limiting embodiments have beenpresented, it should be understood that various changes, substitutions,permutations, and alterations can be made without departing from thescope the appended claims. It will be appreciated that any feature thatis described in connection to any one embodiment may also be applicableto any other embodiment.

It will be understood that the benefits and advantages described abovemay relate to one embodiment or may relate to several embodiments. Theoperations described herein may be carried out in any suitable order, orsimultaneously where appropriate.

Where appropriate, features of any of the embodiments described abovemay be combined with features of any of the other embodiments describedto form further examples having comparable or different properties andaddressing the same or different problems.

It will be understood that the above description of preferredembodiments is given by way of example only and that variousmodifications may be made by those skilled in the art. The abovespecification, examples and data provide a complete description of thestructure and use of exemplary embodiments of the invention. Althoughvarious embodiments of the invention have been described above with acertain degree of particularity, or with reference to one or moreindividual embodiments, those skilled in the art could make numerousalterations to the disclosed embodiments without departing from thescope of the claims.

We claim:
 1. A system for treating a tissue site with reduced pressure,the system comprising: a dressing adapted to be placed adjacent to thetissue site; a reduced-pressure source adapted to be fluidly coupled tothe tissue site; a canister having a fluid reservoir adapted to befluidly coupled to the dressing and the reduced-pressure source; and amoisture trap disposed in the canister and fluidly separating a portionof the fluid reservoir, the moisture trap comprising a barrier and asump adapted to receive condensation from the barrier, the barrierhaving a hydrophilic surface and defining an indirect fluid path betweenthe fluid reservoir and the reduced-pressure source.
 2. The system ofclaim 1, wherein: the barrier comprises plates in parallel juxtapositionand separated to define the indirect fluid path.
 3. The system of claim1, wherein: the barrier comprises plates in parallel juxtaposition andpositioned to define the indirect fluid path; and each of the plates isdisposed in a plane that intersects with the sump.
 4. The system ofclaim 1, wherein: the barrier comprises solid plates in paralleljuxtaposition and positioned to define the indirect fluid path; and eachof the solid plates is disposed in a plane that intersects the sump. 5.The system of claim 1, wherein: the barrier comprises a plate configuredto direct fluid in opposing directions on opposing sides of the plate.6. The system of claim 1, wherein the hydrophilic surface comprises oneor more protrusions.
 7. The system of claim 1, wherein the hydrophilicsurface comprises one or more protrusions in the range of about 15micrometers to about 20 micrometers.
 8. The system of claim 1, whereinthe barrier further comprises a channel adapted to direct condensationto the sump.
 9. The system of claim 1, wherein the barrier furthercomprises a hydrophobic channel adapted to direct condensation to thesump.
 10. The system of claim 1, wherein the barrier further comprises ahydrophobic channel adapted to direct condensation to the sump, and thehydrophilic surface comprises protrusions adapted to direct condensationto the hydrophobic channel.
 11. The system of claim 1, wherein thebarrier comprises a spiral barrier having lateral edges coupled to themoisture trap, a first end disposed proximate to the fluid reservoir,and a second end disposed proximate to the reduced-pressure source. 12.The system of claim 1, wherein the barrier comprises cells havinginterconnected cell walls, the cell walls having perforations definingthe indirect fluid path.
 13. The system of claim 1, wherein the barriercomprises cells having interconnected cell walls, each cell having ahexagonal shape, and the cell walls having perforations defining theindirect fluid path.
 14. The system of claim 1, wherein the barriercomprises cells having interconnected cell walls, each cell having ahexagonal shape having a distance across a flat of about 6 mm, and thecell walls having perforations defining the indirect fluid path.
 15. Thesystem of claim 1, wherein the barrier comprises a mesh having an upperlayer, a lower layer, and fibers coupled between the upper layer and thelower layer, the indirect fluid path defined by spaces between thefibers.
 16. The system of claim 1, wherein the sump comprises anabsorbent.
 17. The system of claim 1, wherein the moisture trap isdisposed within the fluid reservoir of the canister and adjacent to afluid outlet of the canister so that fluid flowing through the canisterpasses through the moisture trap.
 18. The system of claim 1, wherein thebarrier comprises a hydrophilic material having a hydrophobic materialdisposed thereon to form a liquid channel.
 19. The system of claim 1,wherein the barrier comprises a hydrophobic material having ahydrophilic material coated thereon, areas of the hydrophobic materialthat are uncoated forming a liquid channel.
 20. The system of claim 1,wherein the barrier comprises a hydrophilic portion and a hydrophobicportion, the hydrophobic portion forming a liquid channel, and thehydrophilic portion comprising greater than or equal to about 80% of thebarrier.
 21. The system of claim 1, wherein the moisture trap furthercomprises a fluid inlet having a hydrophobic filter disposed thereon sothat fluid flowing through the fluid inlet passes through thehydrophobic filter.
 22. The system of claim 1, wherein the moisture trapfurther comprises a fluid outlet having a hydrophobic filter disposedthereon so that fluid flowing through the fluid outlet passes throughthe hydrophobic filter.
 23. The system of claim 1, wherein the moisturetrap further comprises: a fluid inlet having a hydrophobic filterdisposed thereon so that fluid flowing through the fluid inlet passesthrough the hydrophobic filter; and a fluid outlet having a hydrophobicfilter disposed thereon so that fluid flowing through the fluid outletpasses through the hydrophobic filter.
 24. A moisture trap for removingliquid from fluid in a reduced pressure treatment system, the moisturetrap comprising: a fluid inlet configured to be fluidly coupled to areduced-pressure inlet of a canister; a fluid outlet configured to befluidly coupled to a reduced-pressure source; a barrier disposed betweenthe fluid inlet and the fluid outlet to provide an indirect fluid pathbetween the fluid reservoir and the reduced-pressure source, the barrierhaving a hydrophilic surface; and a sump adapted to receive condensationfrom the barrier; wherein the moisture trap forms a separately enclosedspace within the canister.
 25. The moisture trap of claim 24, whereinthe barrier comprises plates in parallel juxtaposition and positioned todefine the indirect fluid path.
 26. The moisture trap of claim 24,wherein: the barrier comprises plates in parallel juxtaposition andpositioned to provide the indirect fluid path; and each of the plates isdisposed in a plane that intersects the sump.
 27. The moisture trap ofclaim 24, wherein: the barrier comprises solid plates in paralleljuxtaposition and positioned to provide the indirect fluid path; andeach of the solid plates is disposed in a plane that intersects thesump.
 28. The moisture trap of claim 24, wherein the barrier comprisesplates in parallel juxtaposition and configured to direct fluid inopposing directions on opposing sides of each plate.
 29. The moisturetrap of claim 24, wherein the hydrophilic surface comprises one or moreprotrusions.
 30. The moisture trap of claim 24, wherein the hydrophilicsurface comprises one or more protrusions in the range of about 15micrometers to about 20 micrometers.
 31. The moisture trap of claim 24,wherein the barrier further comprises a channel adapted to directcondensation to the sump.
 32. The moisture trap of claim 24, wherein thebarrier further comprises a hydrophobic channel adapted to directcondensation to the sump.
 33. The moisture trap of claim 24, wherein thebarrier further comprises a hydrophobic channel adapted to directcondensation to the sump, and the hydrophilic surface comprisesprotrusions adapted to direct condensation to the hydrophobic channel.34. The moisture trap of claim 24, wherein the barrier comprises aspiral barrier having a first end disposed proximate to the fluid inletand a second end disposed proximate to the fluid outlet.
 35. Themoisture trap of claim 24, wherein the barrier comprises cells havinginterconnected cell walls, the cell walls having perforations to providethe indirect fluid path.
 36. The moisture trap of claim 24, wherein thebarrier comprises cells having interconnected cell walls, each cellhaving a hexagonal shape, and the cell walls having perforationsproviding the indirect fluid path.
 37. The moisture trap of claim 24,wherein the barrier comprises a mesh having an upper layer, a lowerlayer, and fibers coupled between the upper layer and the lower layer,the indirect fluid path provided by spaces between the fibers of themesh.
 38. The moisture trap of claim 24, wherein the sump comprises anabsorbent.
 39. The moisture trap of claim 24, wherein the barriercomprises a hydrophilic material having a hydrophobic material disposedthereon to form a liquid channel.
 40. The moisture trap of claim 24,wherein the barrier comprises a hydrophobic material having ahydrophilic material coated thereon, areas of the hydrophobic materialthat are uncoated forming a liquid channel.
 41. The moisture trap ofclaim 24, wherein the barrier comprises a hydrophilic portion and ahydrophobic portion, the hydrophobic portion forming a liquid channel,and the hydrophilic portion comprising greater than or equal to about80% of the barrier.
 42. The moisture trap of claim 24, furthercomprising a hydrophobic filter disposed in the fluid inlet so thatfluid flowing through the fluid inlet passes through the hydrophobicfilter.
 43. The moisture trap of claim 24, further comprising ahydrophobic filter disposed in the fluid outlet so that fluid flowingthrough the fluid outlet passes through the hydrophobic filter.
 44. Themoisture trap of claim 24, further comprising: a first hydrophobicfilter disposed in the fluid inlet so that fluid flowing through thefluid inlet passes through the hydrophobic filter; and a secondhydrophobic filter disposed in the fluid outlet so that fluid flowingthrough the fluid outlet passes through the hydrophobic filter.
 45. Amethod for treating a tissue site with reduced pressure, the methodcomprising: disposing a dressing adjacent to the tissue site; fluidlycoupling a reduced-pressure source to the reduced-pressure dressing;drawing fluid from the tissue site with the reduced-pressure source;collecting the fluid in a fluid reservoir fluidly coupled between thedressing and the reduced-pressure source; moving the fluid through amoisture trap forming a separate fluid volume in the fluid reservoir inan indirect fluid path between the fluid reservoir and thereduced-pressure source, wherein the indirect fluid path is formed by abarrier having a hydrophilic surface adapted to condense liquid from thefluid; and channeling the liquid from the hydrophilic surface to a sump.46. The method of claim 45, wherein the indirect fluid path comprises aplurality of protrusions formed in the hydrophilic surface.
 47. A methodof manufacturing a moisture trap for a reduced-pressure therapy system,the method comprising: providing a fluid inlet configured to be fluidlycoupled to a reduced-pressure inlet of a fluid reservoir; providing afluid outlet configured to be fluidly coupled to a reduced-pressuresource; forming a barrier having a hydrophilic surface; positioning thebarrier between the fluid inlet and the fluid outlet to define anindirect fluid path between the fluid reservoir and the reduced-pressuresource; and positioning the barrier within a separately enclosed spacein the fluid reservoir, between the fluid inlet and the fluid outlet todefine an indirect fluid path between the fluid reservoir and thereduced-pressure source; and positioning a sump to receive liquidcondensed by the barrier.
 48. The method of claim 47, wherein formingthe barrier further comprises positioning plates in paralleljuxtaposition and to define the indirect fluid path.
 49. The method ofclaim 47, wherein: forming the barrier further comprises positioningplates in parallel juxtaposition to define the indirect fluid path; anddisposing each of the plates in a plane that intersects the sump. 50.The method of claim 47, wherein: forming the barrier further comprisespositioning solid plates in parallel juxtaposition to define theindirect fluid path; and disposing each of the solid plates in a planethat intersects the sump.
 51. The method of claim 47, wherein formingthe barrier further comprises positioning plates in paralleljuxtaposition and configuring the plates to direct fluid in opposingdirections on opposing sides of each plate.
 52. The method of claim 47,wherein forming the barrier further comprises forming protrusions on thehydrophilic surface.
 53. The method of claim 47, wherein forming thebarrier further comprises forming protrusions on the hydrophilicsurface, wherein the protrusions range between about 15 micrometers toabout 20 micrometers.
 54. The method of claim 47, wherein forming thebarrier further comprises forming a channel adapted to directcondensation to the sump.
 55. The method of claim 47, wherein formingthe barrier further comprises forming a hydrophobic channel adapted todirect condensation to the sump.
 56. The method of claim 47, whereinforming the barrier further comprises forming a hydrophobic channeladapted to direct condensation to the sump, and forming protrusions onthe hydrophilic surface adapted to direct condensation to thehydrophobic channel.
 57. The method of claim 47, wherein forming thebarrier further comprises forming a spiral barrier having a first enddisposed proximate to the fluid reservoir and a second end disposedproximate to the reduced-pressure source.
 58. The method of claim 47,wherein forming the barrier further comprises forming cells havinginterconnected cell walls, and forming perforations in the cell walls todefine the indirect fluid path.
 59. The method of claim 47, whereinforming the barrier further comprises forming cells havinginterconnected cell walls, each cell having a hexagonal shape, andforming perforations on the cell walls to define the indirect fluidpath.
 60. The method of claim 47, wherein forming the barrier furthercomprises forming a mesh having an upper layer, a lower layer, andfibers coupled between the upper layer and the lower layer, and formingspaces between the fibers of the mesh to define the indirect fluid path.61. The method of claim 47, wherein the sump comprises an absorbent. 62.The method of claim 47, wherein the barrier comprises a hydrophilicmaterial and forming the barrier further comprises disposing ahydrophobic material on the barrier to form a channel.
 63. The method ofclaim 47, wherein the barrier comprises a hydrophobic material andforming the barrier further comprises coating a hydrophilic materialonto the hydrophobic material to form a channel, wherein areas of thehydrophobic material that are uncoated form the channel.
 64. The methodof claim 47, wherein forming the barrier further comprises forming eachbarrier with a hydrophilic portion and a hydrophobic portion, forming achannel with the hydrophobic portion, and wherein the hydrophilicportion comprises greater than or equal to about 80% of each barrier.65. The method of claim 47, wherein the method further comprisesdisposing a hydrophobic filter in the fluid inlet so that fluid flowingthrough the fluid inlet passes through the hydrophobic filter.
 66. Themethod of claim 47, wherein the method further comprises disposing ahydrophobic filter in the fluid outlet so that fluid flowing through thefluid outlet passes through the hydrophobic filter.
 67. The method ofclaim 47, wherein the method further comprises: disposing a firsthydrophobic filter in the fluid inlet so that fluid flowing through thefluid inlet passes through the hydrophobic filter; and disposing asecond hydrophobic filter in the fluid outlet so that fluid flowingthrough the fluid outlet passes through the hydrophobic filter.